Wut?

Your OSB is only "fairly flat" ?

How about not perfectly flat - 3/16 pitch over 10' in some spots.

IMO the floor has to be flat for interlocking flooring of any kind. I aslo do not think OSB is a good sub floor material. As for the choice if all else is equal the thicker is better.

What does the manufacturer say about osb subfloor? And the floor not being level?

Why is thicker LVP better?

Is it simply the locking system?

Unique what do you mean by it being warmer and more comfortable?

Flat does not equal level. Is your floor out of flat or out of level?

Out of flat - joists are level. The worst I see is 3/16 over 10’

Meets LVP mg’er specs

Lvp has a layer of clear vinyl over the picture of wood. The thickness of that 'wear' layer is important. It can be 12mil, 20mil or 40mil. 40mil is 1 millimeter thick. What's the wear layer for these products. How about links.

Patricia, OSB is the most common subfloor other than concrete slabs that dominate in the south (generally speaking). Why is it not a good subfloor and what would be used otherwise?

@eftontheinside OSB subfloor with 3/16" difference seems fine for a LVP install. There is no doubt, the thicker, the more solid it feels under your feet besides a stronger lock system. WPC is structured with a softer core which makes it warmer and more comfortable than its SPC counterpart constructed with hard stone composite core.

Don't consider it if it's not embossed in register. That is half the effect of the realism. Worse yet is when sunlight rakes across it and the embossing is random and stands out.

Check out Lion floors... mine is 6.5 eir. Its great.

@unique floors

The WPC makes sense. The SPC seems to dominate in my area.

@Paul F.

Thanks for the suggestion. I did check them out but not available in my area. The EIR with more than 4 pattern repeat seems to be difficult to find. LVP mfg’ers do not do a good job of promoting

Oh yeah, 7 repeats minimum. Buy ONE box before you commit to anything and lay it out. I did that on one floor that had the most amazing realistic knots and I realize that one knot was repeated everywhere... it was ridiculous! Pick limited or very nondescript knots is my advice.

You can buy online at flooret.com They are the most durable wear layer I've ever seen... I think its 20mil or something crazy like that. Only online, although you can buy samples and of course one box to check it out.

Flooret is 20mil on the Signature and 40mil on the top line. They have a longer plank and a longer image for less repeats. They also have Silvan engineered wood made in Sweden for 5.50. Collections - Flooret

Silvan Lyon

Flooret doesn’t list their pattern repeat either.

I’ve considered ordering online but I don’t want to play the installer vs material issue game if it comes up.

40mil wear seems excessive - assuming that is for high traffic commercial applications.

Flooret will give you more info readily if you call them. The 20mil product is 6" x 48" for $2.95SF.. The 40mil Signature line is 9" x 72" at $4.50SF. Good luck.

Did you happen to buy from them?

I talked to them. They are available and willing to explain their choices to help you understand their products. I'd go with engineered European Oak.